Three-dimensional phase transformation by impedance-matched dielectric slabs and generation of hollow beams based on transformation optics

• A method is proposed for the transformation between two arbitrary 3D wavefronts through a flat impedance-matched dielectric material.
• The method is used to convert a solid beam into a hollow beam with desired wavefront.
• By tuning the transformation surface, different hollow beams can be generated.
• The results are further validated by 3D finite-difference time-domain simulations.

We propose a three-dimensional (3D) phase transformation method by an impedance-matched dielectric slab and apply it to generating hollow beams. We first employ transformation optics to establish a method for the transformation between two arbitrary 3D wavefronts through a flat dielectric and impedance-matched material. Then the method is used to convert a solid beam into a hollow beam with desired wavefront. By tuning the transformation surface, different hollow beams can be produced. The results are further validated by 3D finite-difference time-domain simulations.